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Problem with I/O priority management RRS feed

  • Question

  • The performance tuning Guidlines for Windows Server 2008 R2, sais that we can disable the I/O priority management for a disk by setting to zero the following registry setting:

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\{Device GUID}\DeviceParameters\Classpnp\IdlePrioritySupported.

    My problem is that such a registry edit in my server's registry does not exist. I have to create it? If yes how?

    Thanjs

    Friday, December 14, 2012 4:52 PM

Answers

  • Hi,

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\{Device GUID}\DeviceParameters\Classpnp

    This is the key name and IdlePrioritySupported is the value name.


    TechNet Subscriber Support in forum |If you have any feedback on our support, please contact tnmff@microsoft.com.

    Tuesday, December 18, 2012 8:52 AM
  • 1) HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\ should exist.

    2) Can you open devmgmt.msc and check DeviceClassGUID for this device?

    There should be an entry in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\

    3) DeviceParameters\Classpnp\ are keys

    4) inside this create IdlePrioritySupported

    Regards

    Satish

    Thursday, December 20, 2012 9:33 AM

All replies

  • The performance tuning Guidlines for Windows Server 2008 R2, sais that we can disable the I/O priority management for a disk by setting to zero the following registry setting:

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\{Device GUID}\DeviceParameters\Classpnp\IdlePrioritySupported.

    My problem is that such a registry edit in my server's registry does not exist. I have to create it? If yes how?

    Thanjs

    Yes, you can manually create it. It's a REG_DWORD you can toggle from 1 to 0 and back. 

    I/O Priorities

    Windows Server 2008 can specify an internal priority level on individual I/Os. Windows primarily uses this ability to de-prioritize background I/O activity and to give precedence to response-sensitive I/Os (such as, multimedia). However, extensions to file system APIs let applications specify I/O priorities per handle. The storage stack code to sort out and manage I/O priorities has overhead, so if some disks will be targeted only by a single priority of I/Os (such as a SQL database disk), you can improve performance by disabling the I/O priority management for those disks by setting the following registry entry to zero:

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses \{Device GUID}\DeviceParameters\Classpnp\IdlePrioritySupported


    StarWind iSCSI SAN & NAS

    Saturday, December 15, 2012 12:08 AM
  • My worry is that in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\ does not exists {Device GUID}\DeviceParameters\Classpnp\

    For the device i want this in order to create an IdlePrioritySupported Dword parameter. So what I have to ask is the {Device GUID}\DeviceParameters\Classpnp\ are key names?

    Thanks for the support

    Saturday, December 15, 2012 9:28 AM
  • Hi,

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\{Device GUID}\DeviceParameters\Classpnp

    This is the key name and IdlePrioritySupported is the value name.


    TechNet Subscriber Support in forum |If you have any feedback on our support, please contact tnmff@microsoft.com.

    Tuesday, December 18, 2012 8:52 AM
  • 1) HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\ should exist.

    2) Can you open devmgmt.msc and check DeviceClassGUID for this device?

    There should be an entry in HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\DeviceClasses\

    3) DeviceParameters\Classpnp\ are keys

    4) inside this create IdlePrioritySupported

    Regards

    Satish

    Thursday, December 20, 2012 9:33 AM
  • This was done on a windows 10 machine!!!!!!!!!!!!!!!!

    right click on "Start (button)"

    left click on "Device Manager (menu item)"

    double click on "Disk drives (tree item)" in "Device Manager"

    Double click on storage device that you wish to add IdlePrioritySupported  key

    Select details tab

    You should see device description

    click on device description, doing so will drop down a list

    on that list find class guid

    Then right click and copy the guid

    The End

    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceClasses\{4d36e967-e325-11ce-bfc1-08002be10318}\DeviceParameters\Classpnp]
    "IdlePrioritySupported"=dword:00000000

    USE MY GUID ONLY IF IT MATCHES YOURS


    • Edited by Smirk24 Saturday, June 18, 2016 8:46 AM
    Saturday, June 18, 2016 8:45 AM